Vertical carton sealer



Sept. 22, 1959 Filed April 15, 1957 W.G. MIDNIGHT VERTICAL CARTON SEALER 6 Sheets-Sheet 1 INVENTJOR wmsua G. Mnomawr Sept. 22, 1959 w. e. MIDNIGHT VERTICAL CARTON SEALER 6 Sheets-Sheet 3 Filed April 15, 1957 ATT = INVENTOR WILBUR G, MIDNIGHT .3 gdwk flW Mam! Q Sept. 2, 1959 w. G. MIDNIGHT 2,904,941

VERTICAL CARTON SEALER Filed April 15, 1957 6 Sheets-Sheet 4 P INVENTO'? WILBUR GLPIIDNWGHT Wwassuns I 1:1 5414*, fig ,Mw 144 DRAIN 0R ATMOSPHERE Sept. 22, 1959 Filed April 15, 1957 w. e; MIDNIGHT VERTICAL CARTON SEALER 6 Sheets-Sheet 5 IN WILBUR VENTOR G. H wmem' Afrva P 1959 w. G. MIDNIGHT 2,904,941

VERTICAL CARTON SEALER 6 Sheets-Sheet 6 Filed April 15, 1957 UVENFW k0 KOP .53 no ozm INVENTOR wmsun G. MlDNIGHT ZHM W Mau A ni/s United States Patent VERTICAL CARTON SEALER Wilbur G. Midnight, Ogden Dunes Ind. Application April 15, 1957, Serial No. 652,905

16 Claims. (Cl. 53-24) The present invention relates to machines for handling fiberboard or corrugated boxboard shipping cases and more particularly to machines for squaring and sealing shipping cases or cartons of this type which are substantially rectangular in shape and have top and bottom flap closures adapted to be held'in the closed position/by means of glue or other appropriate adhesives.

Shipping cases or cartons, known in the trade as slotted cartons, and made of fiberboard or corrugated boxboard are commonly used for packaging a wide variety of products including canned foods and beverages. When such a shipping case has been filled and glue or adhesive has been applied to the flaps, the latter are closed and held in the closed position with suflicient force applied overa suflicient period of time to insure that there is satisfactory adhesion and proper sealing of thecarton.

Employed in present commercial use for accomplishing this sealing action are horizontal machines which receive packed cartons from the adhesive applying and closing mechanism and maintain a continuous pressure onthe carton flaps as the cartons travel continuously along a conveyor. This pressing mechanism commonly comprises a long series of rollers for exerting a sealing force on the cases. These rollers are generally loosely journaled and forcibly urged against the top and bottom of flaps of the cartons and wide, fiat belts driven at the speed of the passing cartons have been utilized between the rollers and the cartons for both applying a sealing set forth which is adapted to apply a substantially greater and more uniform sealing force to the top and bottom closure flaps of a carton than has been achieved by machines of the type heretofore known, soas to effect a better dispersion of theadhesive into the paper fibers of the carton flaps and a more rapid setting of the adhesive. A further object of the present invention is to provide an improved carton flap sealer machine which will p'reserve the dimensional integrity of the carton during the sealing operation and maintain the carton in a'squared position in all dimensions and the closure flaps in proper alinement and abutting relationthereby improving the handling and stacking characteristics of the shipping carton, enhancing its appearance, and making the closed carton tight against the entrance of dirtand other foreign material. 5 5 Still another object ofthe! present invention is to pro vide an improved vertical carton sealer machine. of the type referred to above which adapted to deliver a procartons.

ICE

cession of sealed shipping cartons to an overhead coa veyor system thereby expediting delivery of thesealedf cartons to the loading or other desired area of the plant without requiringfurther handling or transport of the sealed cartons on the plant floor. If

A further object of the present invention is to provide: an improved carton sealer machine of the foregoing chaff-j acter which is of simple and economical construction and which is arranged in such a manner as to occupy all minimum of floor space in the packing plantwherethe machine is used.

Other objects and advantages of the present inventionf will become apparent as the following description pro? ceeds taken in connection with the accompanying draw-.1 ings wherein:

Figure 1 is a perspective view of a vertical cart sealer machine embodying the present invention.

Fig. 3 is a plan view of the machine taken substan i.

tially in the plane of line 33 of Fig. 2.

Fig. 4 is a section view similar to Fig. 3 but taken substantially in the plane of line 44 of Fig. 2. Fig. 5 is a fragmentary elevation view taken substan l tially in the plane of line 55 of Fig. 2. j Fig. 6 is a diagrammatic representation of a vertical carton sealer mechanism illustrative of the present Kin-1 vention and showing certain supply and control conduits for operating the mechanism.

Fig. 7 is a fragmentary side elevation view of a modi.- fied carton sealer machine showing one means for adf" justing the machine to receive various sizes of cartons. Fig. his a fragmentary elevation View of one endof the machine taken substantially in the plane of line 7a7a of Fig. 7 and showing the end caiton stops. i"

Fig. 8 is a plan view of the adjustable machine taken substantially in the plane of line 8-8 of Fig. 7. Fig. 9 illustrates a further means for adapting the" carton sealer machine for use with various sizes of Fig. 10 is a circuit diagram for the electrical controls for the vertical carton sealer mechanism shown in Fig l and showing the control circuit in the condition where in the elevator mechanism is at the top of its stroke and just prior to the entrance of a carton into the sealer mechanism. a

Fig. 11 is a modified circuit diagram for the 'eleci trical controls for the vertical carton sealer mechanism shown in Fig. 9 and in the same condition of operation.

There is shown in the drawings and will be described... below in detail a preferred embodiment of a vertical carton sealer mechanism and certain modifications thereof. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but, on the contrary, it is intended .to, cover all modifications, alternative constructions, equivalents and uses falling within the spirit and scope of-th invention as expressed in the appended claims.

General organization of the machine Referring more particularly to the drawings, a machine 20 is there shown which represents one illustrative sealer embodiment of thepresent invention. The machine 20 is adapted primarily to receive shipping cases or cartons C having glued and closed, but not sealed, flaps from a packaging and closing machine. The machine 20 be constructed to accommodate a particular size packing case or, alternatively, can be made adjustable to accommodate various sizes and shapes of cases without depart-l ing from the scope of the present invention. Inasmuch as the sealer mechanism illustrative of the present inven= tion is'adapted to receive and seal fiberboard or corrugated paper cases or cartons of various sizes and shapes and filled with various products, and also since the packaging and closing machinery when used does not form axpai't' of the present invention, such machinery has not been shown.

i The sealer machine '20 is organized on a generally rectangular upright frame which inthis instance happens to be divided into a lower section 21 and an upper section'22. The lower section 21 of the frame includes a horizontal extension 23supporting a loading conveyor which in the present instance is formed by a pair of laterally spaced flexible belts 24, 25 riding along a horizontal supporting deck 26. For guiding the packed cartons C as they are fed into the machine 20 by the conveyor belts 24, 25, a pair of laterally spaced guide rails 28 are mounted on the frame extensionx23 and a hold down shoe '29 is provided above the conveyor belts for holding the glued but not sealedcarton top flaps in the closed position and for preventing them from springing open beforerthe carton enters the sealermachine 20. In the machine illustrated, the hold down shoe is adjustably supported on four upright posts 30. Alternatively, the hold down shoe can be adjustably suspended from the frame or mounted in any other suitable manner.

Turning now to the upper section 22 of the main frame, it' will be noted that this section comprises a generally rectangular upright structure having a number of vertical- 1y disposed guide bars 35 mounted therein and adapted to guide the stack S of cases or cartons being moved upwardly through the upper section and prevent them from falling and, if desired, to guide the cartons so as to maintain each individual carton square and with its closure flaps properly alined. Although in one preferred construction two guide members 35 are employed for each vertical side of the cartons being sealed, making a total of eight vertical guide members, it should be understood that any suitable number can be used so long as the desired result is accomplished.

Mounted on the upper end of the upper section is a carton ejector mechanism 36 having an ejector head 37 adapted to bear against the uppermost carton or case in the stack so as to exert a lateral thrust against the end or side of the carton for positively discharging the cantons from the top of the stack. From this point, the cartons can be carried by an overhead conveyor system to other areas in the plant.

During the time the packed and closed cartons are in the stack S, the upper cartons exert a sealing force on the glued flaps of the lower cartons thereby causing the flap adhesive to disperse into the paper fibers where it sets to seal the flaps closed. The use of the series of rollers and belts for exerting this sealing force is thereby eliminated because the weight of the cartons and their contents provides a substantial and effective sealing force on the glued flaps.

The carton squaring mechanism The cartons C, having their flaps glued and closed but not sealed, are carried by the conveyor belts '24, 25, to a squaring mechanism which is located in the lower frame section 21 (Figs. 2, 4, Two distinct arrangements are utilized for squaring the carton so that the flaps, when sealed, are alined and abut each other. As a carton, carried on the conveyor belts 24, 2'5, enters the machine 20, it is halted, by end stops 45, between two parallel vertically spaced plates 46, '47, one of which is fixed to the lower section 21 of the frame and the other of which is movable thereon. To accommodate various sizes of cartons, any suitable means can be provided for adjusting the space between the plates.

At the end of the belts and adjacent the end stops 45 the carton entering the machine 20 engages a limit switch LS1 which closes to energize a suitable motor 48 for advancing the movable plate 46 to engage the'carton and '4 square it against the fixed plate 47. One illustrative form of motor is a piston and cylinder type motor mounted on the machine frame and having a piston rod 49 connected to the movable plate 46.

The squaring motor 48 is operated by pressure fluid such as compressed air supplied by a suitable pump or compressor (not shown). When compressed air is used, air from the cylinder is exhausted to the atmosphere.

Although any suitable pressure fluid can be used, compressed air is particularly desirable by reason of its availability in most packaging plants and because it can be exhausted directly to the atmosphere instead of into a drain system. To control the flow of air to and from the motor 48, a suitable air control valve 51 is utilized and is operatively connected to a solenoid 8-1 in the electrical control circuit of the machine so as to be energized to supply air to the squaring motor cylinder when the limit switch LS-l at the end of the conveyor belt is engaged by a carton and closed (Figs. 6 and 10).

LS-1 is open and when a second solenoid S'2 is energized to shift the control valve 5 1 and reverse the motor 48,

as will be described in more detail below.

Although the end stops 45 which the carton initially engages provide a third alinement surface, the remaining two surfaces of the carton are squared and alined in relation to the first two surfaces by a secondary squaring means comprising a pair of plates 52, 53 which are attached to the frame. These plates define spaced, parallel carton engaging faces disposed at right angles to the first pair of plates 46, 47. In order to accommodate various sizes of cartons, means are provided for varying the space between the squaring plates 52, 53. To this end, either one or both of the plates are adjustably mounted on the frame. One means for suspending these plates comprises an axle 55 fixed to the upper edge of the plates and connected between two slides or trolly wheels '56 guidably supported on a pair of tracks 57 mounted in the frame '21. The plates are held spaced apart by means of adjustable mechanical links 58, such as a screw having a right-hand thread on one end and a left-hand thread on the other, connected between nuts 59 on the squaring plates 52 and 53;. By making both plates adjustable, the cartons are always centered in the machine frame.

To insure that each carton is properly squared, a carton, as it is elevated into the stack S, is simultaneously engaged between the second squaring plates 52, 53 and the first squaring plates 46, 47. A squaring force is thereby exerted on all four sides of the carton at one time. From the squaring means, the cartons are elevated into the upper frame 22 and between the guides 35 as additional cartons are inserted into the bottom of the stack by the elevator mechanism 40. Once the flap adhesive has set, the sealed carton flaps hold the cartons squared and in their finished shape.

Elevator mechanism The elevator assembly, indicated generally at 40, comprises a lift mechanism including a motor such as for example, a pressure fluid operated piston and cylinder motor 61, the piston rod 62 of which is fixed to an elevator plate 63 positioned between the conveyor strips 24, 25 and adapted to lift a carton from the conveyor and elevate it through the squaring mechanism into the stack of cartons S. Pressure fluid such as air is supplied to the elevator motor 61 for raising and lowering the elevator plate 63. This air is under the control of the air control valve 51- and in addition under the separate control of a 2-way elevator control valve 64 in the lifting circuit, of the motor '61. The elevator plate 63 is raised when the at of belt limit switch LS-l is "closed to energize' solenoid S-1 and thereby the 4-way control valve 51 and when the 2-way lifting control valve is energized to the open position by a solenoid 8-3. The direction of the elevator motor 61 is reversed to lower the elevator plate 63 by energizing the solenoid S2 to reverse the position of the air control valve 51. During the return or lowering stroke of the elevator motor 61, the 2-way solenoid operated valve 64 is bypassed by a check valve 65. Because in many instances both the top flaps and the bottom flaps of the carton are freshly glued, or the bottom flaps only are glued, it is desirable to hold the elevator plate 63 against the bottom of the lowermost carton in the stack until a succeeding carton is in a position to be carried to the squaring mechanism. One means of accomplishing this is by inserting an electric eye 67 or other similar switch means in series with the elevator direction reversing solenoid S-2 so that that solenoid is not energized if there is no succeeding carton on the conveyor to engage the bottom flaps of the lowermost carton stack.

In order to prevent a succeeding or following carton from being carried by the conveyors underneath the elevator plate 63 when the plate is in the raised position, the plate is provided with a depending tongue 66 which serves as a gate or stop for succeeding cases. This prevents the elevator mechanism from dropping onto a carton and crushing it and possibly from jamming the machine. The elevator operates in correlation with the squaring mechanism although it is under the independent control of the 2-way valve 64 and solenoid 8-3.

Means are provided for holding the stack of cases within the frame and guides 35 when the elevator plate 63 is withdrawn to receiveanother case. To this end, carton catch means are provided, one illustrative form of which is shown in the drawings although it should be understood that other suitable means may be employed. Referring more particularly to Figs. 2 and 4, the catch mechanism 41 comprises an L-shaped lever swingably mounted on the vertical secondary squaring plates 52, 53 and having carton engaging means or catches 69 extending underneath the lower end of the squaring plates and inwardly between them in such a manner that when the catches 69 are in their innermost position, Stacked cartons will rest on the engaging means 69 and be prevented from falling when the elevator plate 63 is lowered. As shown in the drawings, the swingable L- shaped catch mechanism 41 comprises a pair of legs 71, 72 spaced apart and swingably mounted on ears 73 fixed to the back of the secondary squaring. plates 51, 52.

The carton engaging means 69 forms the other leg of the L-shaped catch mechanism 41 and is secured to the bot: tom of the legs 71, 72 in position to extend beneath the squaring plates 52, 53 and inwardly therefrom to sup port a carton. a

In order to elevate a squared carton into the vertical stack S, the main air control valve 51 being in the position for supplying air to lift the elevator plate 63, the elevator 40 is operated when the catches swing outwardly. The catches 69 are retracted as the catch mechanism 41 swings outwardly under the force of suitable motors, such as pressure fluid operated piston and cylinder type motors 75, 76, the cylinders of which are mounted on cross braces 77 between the catch legs 71, 72, and the piston rods of which abut against the rear surface of the plates 51, 52. With this construction the catches swing outwardly when the motors are energized in one direction and swing inwardly when the motor direction is reversed. The catch motors 75, 76 are energized by a supply of pressure fluid such as air under the control of a valve 78 operated by solenoids S-4 and S-5. When the pressure in the squaring cylinder motor 48 reaches a" predetermined amount, a pressure operated limit switch LS-2 is closed to energize one of'the catch solenoids 8-4 which in turn operates the catch motor valve substantially the same manner as described above.

78 to energize the catch motors 75, 76 for retracting the energize the elevator solenoid S3 and open the elevator valve 64. Air pressure from the air source through the main squaring means and elevator air control valve 51 then raises the elevator plate 63 and the carton carried on it into the stack S. When the case has been raised into position in the stack and between the secondary squaring plates '52, 53, an upper or top-of-stroke limit switch LS-S is actuated to energize the other catch motor controlsolenoid S-5. The catch motor valve 78 is then energized to reverse the catch motors 75, 76 and allow the catch mechanism 41 to swing inwardly and close the catches 69 so that they are inserted beneath the carton on the bottom of the stack for holding that carton and the stack S when the elevator plate 63 is lowered.

Cartons passing through this machine are generally filled and are often heavy, making the stack of cartons also heavy. A substantial force is thus required to insert a carton into the bottom of the stack and at the same time to lift the entire stack of cartons. The bottom carton being inserted into the stack must transmit the lifting force from the elevator plate 63 to the stack and accordinglyyit is desirable that the plate 63 have an area large enough to prevent damage to the bottom carton. For this reason, the elevator plate 63 is constructed as long and as wide as possible so as to support at least two parallel ends of the cartons without interfering with the squaring and catch mechanisms. To this end, the catch plates 69 are bifurcated and the elevator plate 63 is formed with oppositely projecting tongues 81 adapted to pass between the bifurcated portions of the catch plates 69 (Fig. 4). The plate 63, including the tongues, additionally serve to support the glued area of the carton to prevent the flaps from springing open before a sub sequent carton is placed in the stack.

In order to make the carton sealing machine adjustable to accommodate various sizes and thicknesses of cases,"

the spacing between the squaring plates is adjustable as described above and the second pair of squaring plates 52, 53 and catch means 41 carried thereon are mounted for vertical adjustment within the lower frame section 21. One illustrative structure for accomplishing this vertical adjustment is shown in Figs. 7 and 8 and comprises a frame 83 adjustably mounted and guided within the lower frame section by means of elevating screws 84 or the like and carrying the squaring plates 52, 53 in The squaring plates can be raised or lowered by turning a hand crank 85, for example, or by any other suitable mechanical means. When this modification is used, the

operation of the machine is substantially as described above. It will be noted that, by lowering the secondary squaring plates and catch means, and thereby lowering the top-of-stroke limit switch LS5, the stroke of the elevator mechanism 40 is shortened with a substantial saving in compressed air and even a substantial saving in time because the elevator travel is shortened.

As an alternative modification for adapting a sealer machine, of the character or type described above and having the secondary squaring means and catch means fixed in position to receive deep cartons, for use with different sizes of cartons, an auxiliary flap hold-down means can be provided (Fig. 9) to prevent the flaps on shallow cartons from springing open before the carton is elevated into the stack. One such auxiliary flap-hold-down means comprises a bifurcated plate 86 mounted for vertical sliding movement on the catch means 41 adjacent the en-- the carton and is raised with it, 6 When the catches are 7. withdrawn or retracted to permit the carton to. he elevated into the stack, the auxiliary flap-.hold-down plate 86, being mounted on the catch mechanism 41, is also retracted, and at the same time, being free of the elevated carton, drops into. position for holding the flaps of a sue! ceeding carton.

The auxiliary llap=hold-down plate 86 is mounted on the catch mechanism 41 by means of a pair of vertical rods 87 slidingly engaged with brackets extending from from the cross brace 77 between the catch legs 71, 72;. To determine the lowermost position of the plate 86, an adjusting screw and stop 88 is provided on the catch engageable with a cross brace 89 between the rods 87. When the auxiliary flap-hold-down plate 86 is used, means are'provided for elevating the carton before the catchers are retracted. This is accomplished by a 2:

position limit switch LS-6 (Figs. 9 and 11) connected between the pressure switch LS-2 and the catch motor control solenoid S.-..4 and between the pressure limit switch LS-l and the elevator control valve solenoid S-.3,

Carton discharge mechanism Provision is made for positively ejecting a carton from the top of the stack and for doing so even when some adhesive has leaked out; or been spilled between the car- QllS nd has caused the upper carton and the one, next below it to stick together. This action is accomplished by exerting both a downward and a lateral force on the topmost carton and by holding the next to the top carton against lateral movement. As a carton is raised in the stack S, the top carton is positioned in front cf the L-shaped ejector head 37, which comprises a horizontal leg portion 91 and a vertical leg portion 93. Te separate the upper cartons in the event they stick together, the vertical leg 93 applies a force on the upper cartOn at a. point near the interface between the top two cartons. This is accomplished by providing a rounded carton contact surface 94 adjacent the lower edge of the vertical leg 93, and by sloping the inner surface 95 of the leg upwardly and away from the stack of cartons. A downward force on the uppermost carton is exerted by the weight of the ejector mechanism, which is pushed upwardly by the top carton as a carton is inserted into the bottom of the stack by the elevator mechanism. The horizontal leg portion 91 is formed with a lower convex. carton engaging surface 96 for engaging the upper carton surface without digging or gouging into it.

The ejector head 37 is moved inwardly and outwardly by means. of a motor such as a pressure fluid operated cylinder and piston type motor 99 hinged at one end to a frame 100 extending from the upper frame section 22. As before, the pressure fluid most commonly available is compressed air. When the top case has been ejected, the ejector head is retracted by reversing the direction of the motor 99. The discharge mechanism 36 will then drop intoposition in preparation for ejecting a succeeding carton. The shock of an abrupt drop is prevented by the provision of a suitable dashpot or damping mechanism 101. To prevent the outer portion of the vertical leg 93 f o d o pin as an th h. en a n e xt c r c the stack in line to be dischargedas the ejector head is et act slcdkc s c bcr. 0. is P c n the .l ucr Pcr ch cf. c crt ca be hi sl dk hemhsr wil c t. 9. 1. m. c the heat; cat on. in. he. stash.

- ghcr lse thecatch. .0 9. 29.

nd. wi l supp rt the ejector h ad 37 sufficiently to allowit to slide baclc across the top surface of. that. carton without dam ging the carton op or othel se interruptng the op ra i n o the machi e The ci ctc mecha ism i pe by ontrolling he pp c ti n f ir pressure. to. the piston nd cylinde motor 99. This is accomplished by a 4-Way valvellllii positioned to direct pressure fluid to the eject end of the.

motor 99 when a solenoid 5-6 is energized and to direct pressure fluid to the retract end of the motor when a: second solenoid S -.-7 is energized. The former solenoid 5-6 is energized when the top carton engages a feels l1 1 06, swingably mounted on ejector head and having a.

lever 7 for oper tiv ng gement with a limit,

switch L S-S mounted on the cylinder 99. The outer limit of the ejector head is determined by the engage;

ment of a, dog 109, fixed on a rod extending from the head 37, with a limit switch LS-7, also mounted on the cylinder 99, which energizes the retract solenoid S 7 when closed.

The feelers 106 also serve an additional functionwheu the machine is being used for sealing bottom carton flaps only. Inthis application the top flaps have a; tendency to spring open when the carton reaches; the, top of the stack. The head 37 then would; engage the open flaps and crush or otherwise damage them.

In order to. prevent this, the feelers 106 extend dowm a y d. ou a y from h head so as to, engag ny p ucar cn flaps n cam the same inw lyto. a.

clos d Po i o Rsum of operation For purposes of illustration, it will be assumed that the elevator plate is in its raised position and that the control circuits. are as shown in Fig. 10. or Fig. 11 In the machine, the carton is carried by conveyor belts 24, 2 5 to the squaring and elevating mechanism. As. a ton en er th ma hine .0 it c s s h pa h of. he electric. eye 67 which closes. a circuit to energi e the elevator and primary squaring cylindersolenoid $11 which in turn shifts the main air control valve 5.1 to lower the, elevating plate 63 of the elevator mechanism 40 and retract the squaring plate 46. Immediately the pressure switch LS ..2 opens and, when the elevator plate 63 is lowered, the top-of -stroke limit switch LS-S shifts. to the poistion in which it is in series with the catch solenoid $94. The, stop or gate 66 on the elevating plate 63 moves out of the way as the plate is. lowered and, allows an entering carton to be carried by the conyqr elt onto he l er e e n p ate 63- The entering box closes the end of belt limit switch L8 1, thereby energizing the solenoid S-1 to shift the air control valve 51. The squaring cylinder 48 is then upp ed w h. pre u flui o. m h sq n p at 46 to, square the carton between the first squaring plates 46, 47. When the. squaring pressure reaches a predeter; mi c ntt c Pressur t h c os n rg zing. h catc cl nci S d t r by ol o mo ors 75, 76 to retract the catches 69. The retraction of the catch mechanism shifts the catch limit switches, I s -3. and. LS- tci ene g z the ay l olen .v =3 an thereby valve '64 to admit air pressure. to the elevator motor 61 for moving the elevator plate upwardly and lifting the squared carton into the bottom of the stack S, Atthe top of the strokewhen the carton has been inserted mm e. s ack a hetw c t e, s o da y squarin p a s- 1.5 he crrch rckc im t sw t h L57 shifts. t ere-hyi h ch e erses.

the catch motors 75, 76 whereby the catches swing inwardly beneath the inserted carton. As long as packed cartons are entering the machine, the electric eye switch 67 will remain closed and the cycle will be repeated. When the electric eye circuit is open, however, the elevator plate will remain in the raised position and against the bottom of the carton in the stack. In the modification employing an auxiliary flap-hold-down plate, the cycle is Substantially the same, except that the closing of the pressure switch LS-Z on the squaring motor 48 energizes the 2-way valve S3 to cause the lifting motor 61 to elevate the packed carton and to lift the fiap-hold-down plate to a point where the flap-hold-down switch LS-6 is shifted. When this occurs, the elevating action is momentarily stopped, the catches are retracted, and the operation continues as described above.

It should be noted that the operation of each element, e.g. the squaring element, the elevator element, the catch elements, and the discharge element, is dependent upon the completion or satisfaction of certain preliminary operations. For example, the catches will not swing outwardly until the squaring mechanism is operated.

The vertical sealer machine described is capable of squaring and sealing at a fast rate cartons having freshly glued and closed flaps, and has been operated at a rate as high as 40 sealed cartons per minute. A substantial savings in valuable floor space is also possible, and sealed cartons are delivered at an elevator above the floor thereby permitting overhead conveying to other plant areas. A substantial floor area usually taken up by conveyors and the like is thus saved for other uses, and in addition, palletizing and other carton handling steps are eliminated. Furthermore, by performing the squaring and sealing operations simultaneously, carton sealing time is reduced and dirt collecting gaps between the carton flaps are eliminated.

I claim as my invention:

1. A carton sealer for sealing the freshly glued flaps of cartons, comprising in combination, a support frame, a conveyor for introducing cartons having glue freshly applied to their flaps into said support frame and with the freshly glued flaps in a horizontal plane, means mounted on said support frame for squaring said carton, a plurality of spaced vertical guides for holding said squared cartons in stacked vertical alinement, means for positioning the squared cartons onto the bottom of said stack, and means for removing a sealed carton from the top of said stack.

2. A carton flap sealer comprising, in combination, a support frame, a conveyor for carrying cartons to be sealed and for introducing a carton into said frame between a pair of spaced squaring plates, means for actuating said squaring plates to square said carton, a plurality of vertical guide members for holding a stack of said squared cartons in vertical alinement, a pair of catches at the bottom of said guide members, for supporting a stack of cartons within said guides, means for retracting said catches, and means for elevating said squared carton into said stack and between said guides when said catches are retracted.

3. A carton flap sealer comprising, in combination, a support frame, a conveyor for carrying cartons to be sealed and for introducing a carton into said frame between a pair of spaced squaring plates, means for actuating said squaring plates to square said carton, a plurality of vertical guide members for holding a stack of said squared cartons in vertical alinement, a pair of catches at the bottom of said guide members, means for retracting said catches in response to the squaring of said carton,'means for elevating said squared carton into said stack and between said guides when said catches are retracted, said elevating means holding said carton in an elevated position until a succeeding carton is carried on said conveyor into said frame, and means for engaging said catches beneath the elevated carton when said elevating means is lowered thereby to hold a stack of squar ed cartons said support frame.

4. A mechanism for vertically stacking paperboard cartons, the flaps of which are coated with freshly applied adhesive and then folded and closed to a horizore tal position, said mechanismcomprising in combination, a vertically extending frame having spaced guide members mounted therein for holding such cartons in a vertical stack until the adhesive on the flaps sets, catch means for engaging the bottom of the lowermost carton carton on the bottom of the stack.

5. A mechanism for vertically stacking paperboard cartons the flaps of which are coated with freshly applied adhesive and then folded and closed to a'horizontal position, said mechanism comprising in combination, a vertically extending frame having spaced guide members mounted therein for holding such cartons square and in a vertical stack until the adhesive on the flaps sets, catch means for engaging the bottom of the lowermost carton in the stack to prevent the stack of cartonsl from dropping out of said frame, means for squaring a carton preliminary to the introduction of the same into the bottom of the stack, means operative in response to the operation of said squaring means for relasingsaid.

catches, means operative in response to the release of said catches for positioning said squared carton on the bottom of the stack, and means operative in response to the positioning of a squared carton on the bottom of the stack for repositioningsaid catches beneath the stack,

6. A mechanism for vertically stacking paperboard cartons the flaps of which are coated with freshly applied adhesive and then folded and closed to a horizontal posi t on, said mechanism comprising in combination, a ver-, tlcally extending frame having spaced guide members mounted thereinfor holding such cartons square and in a vertical stack until the adhesive on the flaps sets, catch means for engaging the bottom of the lowermost carton in the stack to prevent the stack of cartons from dropping out of said frame, means for squaring a carton preliminary to the introduction of the same into the bottom of the stack, means for releasing said catches, means for positioning said squared carton on the bottom of the stack, and means engageable with the topmost carton in the stack for removing such carton from the stack, said carton positioning means being operative in response to the operation of said catch releasing means to release said catches which is in turn operative in response to the operation of said squaring means to square a carton,

7. A mechanism for vertically stacking paperboard cartons the flaps of which are coated with. freshly applied adhesive and then folded and closed to a horizontal position, said mechanism comprising incombination, a vertically extending frame having spaced guide members mounted therein for holding such cartons in a vertical stack until the adhesive on the flaps sets, catch means for engaging the bottom of the lowermost carton in the stack to prevent the stack of cartons from, dropping out of said frame, first squaring means for squaring a carton preliminary to the introduction of the same into the bottom of the stack, means for positioning said squared carton on the bottom of the stack, and second squaring means positioned substantially perpendicular to said first squaring means. for completing the squaring of carton as it is positioned in the stack.

8. A mechanism for vertically stacking paperboard cartons the flaps of which are coated with freshly applied adhesive and then folded and closed to a horizontal position, said mechanism comprising in combination, a vertically extending frame having spaced guide members mounted therein for holding such cartons square and in au/ertical stack until the adhesive, on the flaps sets, first squaring means for squaring a carton prelimiary to the introduction ofthe same, into the bottom of the stack, secand squaring means positioned substantially perpendicular to said first squaring meansfor completing the squaring of the carton, catch means mounted on said second squaring means for engaging the bottom of the lower most carton in the stack to prevent the stack of cartons from dropping out of said frame, means operative in response to the operation of said first squaring me'ans for releasing said catcheslandmeans operative in response to. the release of said catches for positioning said squared carton on the bottom of the stack.

9. A mechanism for vertically stacking paperboard cartons the flaps of which are coated with freshly applied adhesive and then folded and closedto, a. horizontal position, said mechanism comprising in combination, a vertically extending frame having spaced guide members mounted therein for holding such canons square and in a' vertical stack until the adhesive on the flaps sets, means for positioning a carton on the bottom of said stack, catch means for engaging the 'bottom of the lowermost carton in the stack to prevent the stack of cartons from dropping out of said frame, first. squaring means for squaring a carton preliminary to the introduction of the same into the bottom of the stack, second squaring means positioned substantially perpendicular tosaid first. squarmg means for completing the squaring of the carton, said first and second squaring means engaging the, cartons:

simultaneously as, the. catton is positioned on the bottom of the Stack, said catch means being mounted on said second squaring means and extending there beneath for engagement with the lowermost staclc carton.

L0,. The method of sealing freshly glued horizontally folded flaps of paperboard and corrugated boxboard cartons comprising the steps. of aligning the vertical sides of a carton having freshly glued flaps in squared rectangular relation, exerting a, sealing force on said flaps by placing said squared, carton onto the bottom of a vertical stack of similarly squared cartons, and ejecting said carton after it has been subjected to said sealing force by being raised to a preselected elevation in the stack as u cessive, squared cartons are p aced below it in the stack.

I 11. The method of sealing freshly glued horizontally folded flaps of paperboard and corrugated boxboard cartons comprising the, steps, of aligning the vertical sides of a carton having freshly glued flaps in squared rectangular relation, exe ting a sealing force on said flaps by placing sa d squared carton onto thebottorn of avertical stack of similarly squared cartons, inserting successive squared: cartons having freshly glued flaps, into the bottom of said stack, and ejecting said cartons from the, stack after they have been raised to a preselected elevation in the stack.

12. A carton sealer for sealing freshly glued flaps of cartons by stacking the cartons in vertical relation with the freshly glued flaps horizontal to utilize, the weight of the stacked carton as the flap sealing force, said sealer comprising in combination, a support frame, a conveyor on said frame for successively positioning in the sealer cartons having freshly glued horizontally disposed flaps,

a first pair of spaced pressure plates guidably mounted on said frame adjacent to and on opposite sides of said conveyor for engaging opposite side Walls of a carton, an actuator for positioning said plates in squaring engagement with the cartons, a second pair of spaced squaring plates mounted on said frame above said conveyor for squaring; the opposite vertical end walls of the cartons, an elevator plate aligned between said squaring-plates and engageable with the bottom of; the carton, an actuator for rat" ing said elevator plate to lift the cartons one at a ti e from betweensaid first pair of Squaring plates into a vertical stack, of cartons between said second pair of. squaring plates, a catch engageable with the bottom of the lowermost elevated carton for supporting the stack of cartons between said second pair of squaring plates as said actuators lower the elevator plate and separate the first pair of squaring plates, said conveyor positioning subsequent cartons having freshly glued flaps in the sealer for squaring and elevation into the stack of cartons, and a discharge mechanism located at a predetermined height above the conveyor for discharging the topmost carton from the stack.

13. A carton sealer for sealing freshly glued flaps of cartons by stacking the cartons in vertical relation with the freshly glued flaps horizontally disposed to utilize the Weight of the stacked carton as the flap sealing force, said sealer comprising in combination, a support frame, means for successively conveying into the sealer cartons having freshly glued horizontal flaps, means for squaring a carton positioned in the sealer by said conveying means, means aligned between said squaring means and engage able, with the bottom of the carton for lifting the cartons one at a time from between said squaring means into a vertical stack of cartons, and means located at a predetermined height above the conveyor means for discharging the topmost squared and sealed carton from the stack.

14. A mechanism for vertically stacking paperboard cartons, the. flaps of which are coated with freshly applied adhesive and then folded and closed to a horizontal position, said mechanism comprising, in combination, a vertically extending frame for supporting a vertical stack of cartons until the adhesive on the carton flaps sets, means for positioning cartons having closed but not sealed flaps one at a time into the bottom of the stack, means for engaging the bottom of the lowermost carton in the stack to prevent thestack of cartons from dropping out of said frame, means for releasing said engaging means when said positioning means inserts a carton into the stack, and means for removing sealed cartons one at a time from the top of the stack.

15. A carton sealer for sealing the freshly glued flaps V of cartons, comprising in combination, a support frame, a conveyor for introducing cartons having glue freshly applied to their flaps into said support frame and with. the freshly glued flaps in a horizontal plane, a plurality of spaced vertical guides for holding said cartons in stacked vertical alinement, means for positioning the cartons onto the bottom of said stack, and means for removling a sealed carton from the top of said stack.

16. A mechanism for Vertically stacking paperboard cartons, the flaps of Which are coated with freshly applied adhesive and then folded and closed to a horizontal position, said mechanism comprising in combination, a vertically extending frame having spaced guide members mounted therein for holding such cartons in a vertical stack until the adhesive on the flaps sets, means. for conveying a carton having glued, folded and closed flaps into said frame, catch means for engaging the bottom of the lowermost carton in the stack to prevent the stack of cartons from dropping out of said frame, means re.- ceiving cartons from said conveyor for positioning said cartons one at a time on the bottom of the stack, and

means for removing sealed cartons one at a time from the 'top of said stack.

References Cited in the file of this patent UNITED STATES PATENTS 

